Composite tube for torque and/or load transmissions and related methods

ABSTRACT

A composite tube made from a combination fiber and epoxy is disclosed. The tube may be made by filament winding although other materials and processes are suitable. In one example, the tube laminate is a mix of axial and helical fibers tailored to meet the stiffness and strength requirements of the particular application. Fibers having a different modulus may also be mixed to meet axial and torsional stiffness requirements. For example, high modulus fibers may be used in a helical pattern to handle high torque loads while lower modulus fibers may be used for the remaining portion of the tube laminate. The composite tube may be used for load and/or torque bearing applications and can include a support tube pressed fit into an end of the tube.

BACKGROUND

Engineers in general and automotive engineers in particular continuouslystrive for weight reduction in vehicles without compromising strength,reliability and crash worthiness. Composite materials, such as carbonfiber/epoxy composites, can provide the weight reduction and strengthrequired by engineers. However, the connection of a composite materialcomponent to a traditional metallic automotive component can beproblematic. This is particularly the case when composite material needsto be attached to traditional drive-line components, such as the enginebell housing, the transaxle, the transmission, or the differential gearunit, as non-limiting examples.

Front engine automobiles having a rear transaxle are attractive toautomotive engineers because of the more equal weight distributionbetween the front and rear tires. Traditionally, the transaxle designuses the auto frame to hold the relative position of the engine to thetransaxle and react torque loads. A drive shaft provides the powertransmission between the engine and the transaxle.

A structural tube, also known as a torque tube, is typically providedbetween the engine and the transaxle and concentric around the driveshaft to provide a direct tie for the two components. The drive shaftruns through this structural tube. The structural tube must resistbending and torque loads between the engine and the transaxle. A carbonfiber composite tube is ideal for this application because of itslightweight, strength and dampening characteristics. A carbon fibercomposite structural tube can be efficiently made by the filamentwinding process. The carbon fibers can be tailored in their orientationand thickness to meet the bending and torsional stiffness and strengthrequirements for such an application. While designing and manufacturinga carbon fiber/epoxy structural tube for the engine/transaxle torquetube application is relatively easy, the joint between the engine bellhousing and the transaxle nose housing and the carbon fiber compositetorque tube can be problematic.

Fasteners are often used to tie metallic and composite structuralcomponents together. However, fasteners add cost and are not attractivefor high volume automotive applications. Welding components together iscost effective and typical for the auto industry but is not possible forcomposites. Adhesive bonded joints may be used but typically requireexternal fixtures to hold the assemblies, such as to hold theengine/transaxle torque tube assembly, while the adhesive cures, whichcan be too slow for high volume automotive production.

Interference “press fit” joints are common for the automotive industrybut may not be suitable for composites. If a carbon fiber/epoxy tube was“pressed fit” into or has a “press-fit” arrangement or joint withaluminum or steel bell housing for the engine/transaxle torque tubeapplication, the composite could creep when subjected to under the hoodand road temperatures. This in turn can compromise the interference fitand lead to separation. If adhesive was applied to a carbon fiber tubeand it was slipped fit into the engine or transaxle housing, theadhesive would be scraped-off during installation and the strength ofthe bond could be compromised and highly variable.

SUMMARY

Aspects of the present system and device include a drive train for avehicle comprising an engine component housing comprising a hub havingan inside diameter defining a bore. For example, the engine componenthousing can be a bell housing, a transmission housing, or a transaxlehousing of an automobile, truck, or recreational vehicle. The drivetrain can further comprise a composite tube comprising an outer diameterpositioned within the bore of the hub of the engine component housingwith said composite tube comprising a bore comprising an inner diameter.To resist and/or prevent creep, a support tube is located inside thebore of the composite tube. Preferably, the support tube and thecomposite tube are in an interference fit and preferably the hub of theengine component housing and the composite torque tube are in aninterference fit. In an example, adhesive bond is applied to bond thecomposite tube and the engine component together.

The drive train wherein the support tube is made from a metallicmaterial, such as from aluminum, is disclosed.

The drive train can further comprise a hole formed in the hub of theengine component housing and wherein a fitting is connected to the holeto permit adhesive application into the connection joint.

The drive train can further comprise undercut formed in the bore of thehub of the engine component housing or the composite tube.

The drive train wherein the composite tube has a second end and whereina second support tube is pressed fit into the second end.

The drive train wherein a portion of the composite tube that ispositioned within the bore of the hub of the engine component housingcan have a clean-up machined surface.

The drive train wherein the support tube has an end most part and thecomposite tube has an end most part and wherein the two end most partscan align.

The drive train can further comprise a drive shaft located inside thecomposite tube and within the support tube.

The drive train wherein the engine component housing is a bell housingor a slip-on yoke.

Another aspect of the present device and system comprises a shaft piececomprising a metallic sleeve pressed fit into a composite tube with aninterference fit such that when the composite tube is subsequentlypressed fit into a metallic hub, the composite tube is sandwichedbetween two metallic interfaces with an interference pre-load on aninside surface of the composite tube and on an outside surface of thecomposite tube.

The shaft piece wherein the metallic hub is connected to a flangecomprising a bolt pattern is disclosed.

The shaft piece wherein the metallic hub is part of a slip-on yokecomprising at least two connecting bosses is disclosed.

The shaft piece wherein the metallic hub is part of a bell housing of anautomobile drive train is disclosed.

The shaft piece wherein the metallic hub is part of a gear box isdisclosed.

The shaft piece wherein the metallic hub is connected to a flange, whichis connected to a fan assembly, is disclosed.

A still further feature of the present device and system is a mechanicaljoint for an automotive driveline assembly connecting an engine and atransaxle, said mechanical joint comprising adhesive injected into arelief space machined in a press-fit joint of a composite tube and ametallic hub so that assembly between the composite tube and themetallic hub is self-fixturing while the adhesive cures.

Yet another aspect of the present disclosure is a method for forming ashaft piece. The method can comprise forming a composite tube comprisinga first end and a second end; said first end comprising a bore, anexterior surface, and an interior surface. The method further comprisesthe steps of placing a support tube into the bore of the first end in apress-fit arrangement and placing the composite tube with the supporttube into a bore of a metallic structure in a press-fit arrangement withthe metallic structure.

The method can further comprise machining an undercut in the bore of themetallic structure prior to placing the composite tube therein or anundercut on the OD of the composite tube.

The method can further comprise pressuring adhesive through a holeformed in the bore of the metallic structure.

The method wherein the shaft piece is usable in a cooling towerapplication or an automotive application.

The method can further comprise placing a metallic support tube into thecomposite tube at the second end.

The method can further comprise aligning an end most part of the supporttube with an end most part of the first end.

Still yet another aspect of the present disclosure is a drive train fora vehicle. The drive tran can comprise an engine component housingcomprising a hub having an inside diameter defining a bore, an outsidediameter, and a thickness therebetween; a composite tube comprising anouter diameter and an inner diameter pressed fit with the hub of theengine component housing, said composite tube comprising a bore; asupport tube mounted inside the bore of the composite tube or over theouter diameter of the composite tube in an interference; and wherein thehub of the engine component housing and the composite torque tube areadhesively bonded together.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present device, system,and method will become appreciated as the same becomes better understoodwith reference to the specification, claims and appended drawingswherein:

FIG. 1 is a schematic diagram depicting a drive train provided inaccordance with aspects of the present disclosure.

FIG. 2 is a partial cross-sectional side view of the drive train of FIG.1, viewed at the first end of the torque tube.

FIG. 3 is a blown up view of detail A of FIG. 2.

FIG. 4 is a schematic view of a drive shaft assembly provided inaccordance with aspects of the present disclosure.

FIG. 5 is a connection system provided in accordance with aspects of thepresent disclosure.

FIG. 6 is a cooling tower comprising a fan assembly provided inaccordance with aspects of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of the presently preferredembodiments of composite tube for torque and/or load transmissionsprovided in accordance with aspects of the present device, system, andmethod and is not intended to represent the only forms in which thepresent device, system, and method may be constructed or utilized. Thedescription sets forth the features and the steps for constructing andusing the embodiments of the present device, system, and method inconnection with the illustrated embodiments. It is to be understood,however, that the same or equivalent functions and structures may beaccomplished by different embodiments that are also intended to beencompassed within the spirit and scope of the present disclosure. Asdenoted elsewhere herein, like element numbers are intended to indicatelike or similar elements or features.

In an exemplary embodiment of the present device, system, and method, anelongated composite tube is provided, which is preferably made from acombination of fiber and epoxy and is capable of load and/or torquebearing. The tube may be made by filament winding although othermaterials and processes are also suitable. In one example, the tubelaminate is a mix of axial and helical fibers tailored to meet thestiffness and strength requirements of the particular automobile. Fibershaving a different modulus may also be mixed to meet axial and torsionalstiffness requirements. For example, high modulus fibers may be used ina helical pattern to handle high torque loads while lower modulus (andlower cost) fibers may be used for the remaining portion of the tubelaminate.

With reference now to FIG. 1, a schematic diagram showing a drive train100 for an automobile comprising an engine 102 supported on the frame atthe front engine mount 104 is provided. A clutch unit 106 is attached tothe engine 102 and to a transmission 108. To drive the rear wheels, adrive shaft 110 is provided for connecting the transmission to the reardifferential gear unit 112, which is supported by the rear mount 114. Atorque tube or shaft 116 is located externally of the drive shaft 110.The torque tube 116 is configured to get the traction forces generatedby the wheels to the car frame. As shown, the torque tube 116 is madefrom a composite material, such as by filament winding around a mandrel,and is attachable to the bell housing 118 at its first end 120 and tothe transmission housing at its second end 122. The connection at thefirst end 120, the second end 122, or both can include the innovativeconnection joint 124 provided in accordance with aspects of the presentdisclosure.

FIG. 2 is a partial cross-sectional view of the drive train 100 of FIG.1 and more specifically of the connection joint 124 at the first end 120of the drive train. As shown, the bell housing 118 has an inlet 126 forreceiving the torque tube 116. The inlet 126 may be referred to as ahub. In other examples, the bell housing 118 may embody any number ofengine components that accepts or receives a shaft, such as a compositetube of the present disclosure. The torque tube 116 is made from acomposite material, such as from a carbon fiber/epoxy combination, tocontribute to the overall weight reduction of the drive train. Toenhance the connection, an inner support tube 128 is pressed fit intothe open end 130 of the composite tube 116 to support the composite tube116, as further discussed below. In an embodiment, the support tube 128is made from a metallic material, which in a preferred embodiment isaluminum.

In one example, the support tube 128 can have approximately the samethickness as the torque tube 116 but can be smaller or larger dependingon the temperature, load and other operating parameters of theparticular application. In an embodiment, the length of the support tube128 is typically one (1) time the composite tube diameter. Thus, if thetube diameter is 3.3 inches, then the length of the support tube 128 is3.3 inches. In another example, the length of the support tube 128 canbe longer or shorter than the diameter of the composite tube 116. Asshown, the support tube 128 is pressed fit into the open end 130 of thecomposite tube 116 and slid or forced into the composite tube until theend-most parts 132, 134 of the two tubes 116, 128, respectively, aregenerally flushed or even. In a less preferred embodiment, the end-mostpart 134 of the support tube 128 extends further into the bell housing118 than the end-most part 132 of the composite tube 116. In yet anotherexample, the end most part 134 of the inner support tube 128 residescompletely inside the torque tube 116. The composite tube 116 can varyin length depending on the application. For example, the composite tube116 can extend about 4 feet to 7 feet in length from the first end tothe second end or even longer. Where the composite tube is used as acoupling or a pipe section, the range can be even greater, extendingfrom about 1.5 feet to about 10 feet. Generally speaking, the longer thecomposite tube 116, the stiffer and stronger it is made, which generallyincludes a relatively thicker walled tube.

The support tube 128 is configured to prevent the composite tube 116from creeping and/or to resist creeping when the composite tube ispressed fit into the engine bell housing 118. For example, when theinlet 126 of the bell housing squeezes the end 120 of the composite tube116 due to the interference fit between the bell housing and the torquetube and the drive train 100 is at elevated temperatures, such as duringservice, the fibers of the torque tube can move or creep. Consequently,composite materials are seldom employed for certain automotiveapplications and at certain elevated temperatures. However, bysupporting the first end 120 of the composite tube 116 with a supporttube 128, it is possible to expand the use of composite materials forautomotive and other applications, as further discussed below. Note thateven when the service temperature is not elevated, the connection joint124 using a support tube of the present disclosure may still beemployed.

The second end 122 of the composite tube 116 (FIG. 1) may similarly beequipped with a support tube 128 (not shown) for press fitting thesecond end into the transaxle nose housing or transmission housing. Insome embodiments, the composite tube 116 is first attached to a hubportion of a flange member (not shown). The flange member is thenattached to a mating flange of the transaxle housing, the differentialgear unit or the power transmission unit, and the mated flanges arebolted together. In embodiments with a flange member, the composite tube116 may be attached to the hub portion of the flange member in the samemanner or fashion as discussed herein for installing the composite tubeinto the hub of the bell housing 118, as further discussed below. In yetother examples, the composite tube 116 is attached to a hub portion thatis then attached to a yoke. The yoke is then attached to a universaljoint, which can be attached to an axle yoke or other rotating members,as further discussed below.

When aluminum is used for the support tube 128, the thermal expansion ofthe aluminum internal sleeve maintains a preload over and above theinitial interference fit on the composite tube 116 as the engine bellhousing and the transaxle housing temperatures increase during serviceor operation. In one example, the insertion amount of the composite tube116 with its internal aluminum support sleeve 128 into the engine bellhousing 118 and at the other end 122 to a transaxle nose or transmissionhousing (FIG. 1) is less than one (1) time the diameter of the compositetube 116 to prevent or minimize local stress concentrations at theconnection. That is, the overlap between the bell housing 118 and thecomposite tube 116 is preferably less than the diameter of the compositetube to prevent or minimize local stress concentration around the end ofthe composite tube caused by the press-fit arrangement. In a particularexample, the overlap between the bell housing and the composite tube isabout 20% to 90% of the diameter of the composite tube while the overlapbetween the support tube 128 and the composite tube 116 is about 85% to125% of the diameter of the support tube, with the latter figure for asupport tube that is longer in length than the diameter of the compositetube. Less preferably, the composite tube 116 can be inserted a distanceinto the inlet 126 of the bell housing 118 that is approximately between0.9 to 1.2 times that of the tube diameter.

With particular reference to FIG. 3, the composite tube 116 has aclean-up machining cut 136 on the outside surface or area 138 that isinserted into the bell housing 118, and a similar cut on the oppositeend 122 for insertion into the transaxle housing, hub portion,differential gear unit or transmission unit, to achieve a desiredinterference fit. The clean-up cut 138 simply creates a precisionmachined surface to provide a desired interference fit. In an example,the interference is roughly 0.005 inches to about 0.012 inches with0.008 inches being more common. Even though a clean-up machining cut isapplied to the outside surface of the composite tube, the structuralfibers extend into the over-lap joint.

To further enhance the connection joint 124 between the bell housing 118and the composite tube 116, and on the other end 122 of the compositetube with a second end structure that the second end connects to, arecess or undercut 140 is provided on the inside surface of the inlet orhub 126 of the bell housing 118. In one example, the recess or undercut140 embodies a relief machined in the inside surface of the bell housing118, and of the second end structure for the second end 122 of thecomposite tube, to provide space for epoxy adhesive. For example, whenepoxy is added to the joint to secure the two components, a tiny spaceis provided by the undercut 140 to facilitate distribution of theadhesive. In one example, the undercut 140 is formed circumferentiallyaround the inlet 126 of the bell housing to a depth of about 0.005inches to about 0.040 inches. In alternative embodiments, spiral groovesare formed as undercuts for adhesive flow. In still yet otherembodiments, spaced apart axial grooves are formed as undercuts withchannels or gaps formed between them for fluid adhesive distribution.

An assembly hole 142 is provided in the bell housing 118 to allow epoxyadhesive to be injected into the connection joint 124, and moreparticularly to the undercut section or sections 140 of the inlet 126. Azerk fitting or similar fitting may be used with the assembly hole 120to inject epoxy adhesive into the undercut section or sections 140. Inan alternative embodiment, two or more holes with two or more fittingsare used to inject the epoxy adhesive. Excess adhesive can drain out adrain hole 144 located some distance from the assembly hole 142. In apreferred embodiment, the second hole or drain hole 144 is locatedopposite the assembly hole. The adhesive is pressurized in the joint orrecessed space 140 and completely fills the relief space. Without theundercut, it may not be possible to apply adhesive to the parts beforeslipping them together as adhesive can scrape off during the fit-upprocess. This relief is approximately 60% of the overall insertionlength of the joint. For example, if the overlap length between the bellhousing and the composite tube is 2 inches long, then the relief isabout 1.2 inches in axial length. In other examples, the relief can begreater than 60% and as low as about 30%. Once connected, the compositetube 116 is understood to be mounted to two hubs or inlets 126, which inthe present embodiment are secured to stationary housing structures,such as part of a bell housing and part of a transmission housing.

As understood by the present disclosure, several varied approaches arecombined to produce a reliable and cost effective connection joint.First, the composite tube 116 is inserted into the bell housing 118 andthe second end 122 is inserted into the second end structure with aninterference fit at both ends. Second, deformation or “creep” of thecomposite tube 116, which normally would result in compromising thestrength of the interference fit, is addressed by the support tube 128that is positioned on the inside of the composite tube 116 to resistcreep deformation caused by the interference fit with the bell housing118. The composite tube 116 is sandwiched between the bell housing 118and the support tube 128, which are both preferably made from metallicmaterials with each having an interference fit on the inside diameterand the outside diameter of the composite tube, respectively.

A similar configuration but with a different second end structure isarranged on the second end 122 of the composite tube 116. In analternative embodiment, the second end 122 of the support tube is bondedto another composite structure but without a support tube, such as forwhen creep is not an issue at the second end 122. Further alternatively,the second end is inserted into a slip-on flange or a hub with a boltedconnection to a second end structure. After assembly, epoxy adhesive isinjected into the mated joints provided by a recessed space or undercutmachined into the bell housing and into the second end structure. Therecessed space 140 is filled and is allowed to cure. This joint 124 isself-fixturing by virtue of the interference fit so no adhesive bondingfixtures, such as clamps or support rigging, are required to hold thecomponents together during curing and the parts can be moved down theassembly line while curing. The adhesive bond supplements the press-fitarrangement to resist bending stresses from axle torque which may not becarried as well by a press-fit connection alone. The adhesive bond isconfigured to carry the high bending and torque loads typicallyassociated with torque or load bearing shafts. The composite tube 116expands into the relief gap or undercut after being pressed fit into thebell housing 118, which increases the strength of the press-fit andreduces the bond line gap. The combination of the three elements of thejoint design 124 make for a robust connection that is low cost toproduce and suitable for high volume production.

In some embodiments, the location of the support tube 128 is modified.For example, the support tube 128 may be placed around the exterior,such as pressed fit over the OD, of the composite tube 116. To mount themodified reinforced shaft with the support tube 128 on the outside, thehub, such as the bell housing 118 of FIG. 2, is pressed fit to theinterior surface, such as pressed fit to the ID, of the support tube116. Similar overlapping and interference may be used as described abovefor the reversed arrangement. When the support tube is mounted to theoutside of the composite tube, a fill hole 142 and a drain hole 144 maybe incorporated in the support tube.

With reference now to FIG. 4, a drive shaft assembly 150 provided inaccordance with another aspect of the present system, device and methodis shown. The drive shaft assembly 150 comprises a tube assembly 152comprising a torque tube 154 having a slip on yoke 156 located at thefirst end 158 and the second end 160 of the torque tube 154. The yoke156 each comprises a hub 162 and a connection flange 164 comprising twoconnection bosses 165 and is typically made from a metal, such as carbonsteel. The hub 162 is hollow and a bore defined by the wall surfaces ofthe hub extend towards the end wall 166 of the connection flange 164.

As shown, the torque tube 154 is made from a composite material, such asby a filament winding process similar to the process described above forthe composite tube 116. The tube 154 may be attached to the two hubs 162using the process described above for connecting the composite tube 116to the bell housing 118. The torque tube 154 is configured for rotatableapplications. Thus, the tube assembly 152 further comprises two metallicsupport tubes (not shown) mounted internally at each end 158, 160 of thetorque tube 154 and pressed-fit to the torque tube. The drive shaftassembly 150 further comprises a universal joint 170, an axle yoke 172,and a driver or driven shaft 174, which is connected to the axle yoke.The drive shaft assembly 150 may be part of any number of automotivedrive train systems from any number of automobile manufacturers.

As described, aspects of the present disclosure are understood toinclude a device, system, and method comprising a composite shaft ortube connected to a hub at each end of the tube. The device, system andmethod are further understood to include a flange for use in a rotatableapplication. In an alternative embodiment, the two hubs are connected toor are part of stationary housings for use in a stationary application.As shown in FIG. 4, the two flanges are part of a yoke assembly. Inother embodiments, the flanges have a generally planar bolt pattern forbolting to a mating flange having a similar bolting pattern. Thealternative configuration with a bolt pattern is typically found in pipelines and in shaft couplings, among other applications, and resemblesthe assembly shown in FIG. 5.

With reference now to FIG. 5, a connection system 180 provided inaccordance with aspects of the present disclosure is shown. Theconnection system 180 comprises a shaft piece 181 comprising a flange182 comprising a bolt pattern 184 with a plurality of bolt holes 186. Ahub 188 is attached to the flange 182, which defines a bore forreceiving a pipe, shaft, or tube 190. In the disclosed embodiment, thetube 190 is made from a composite material, such as by a filamentwinding process, similar to the process described above for thecomposite tube 116. The tube 190 may be attached to the hub 188 usingthe same process described above for connecting the composite tube 116to the bell housing 118. Thus, the shaft piece 181 further comprises asupport tube (not shown) mounted internally in a press-fit configurationat the first end 192 to resist and/or prevent creep. The second end (notshown) of the shaft piece 181 may be connected to a similar hub andflange as shown in FIG. 5. In an alternative embodiment, the flange atthe second end may have a different flange type with a different flangepattern. The shaft piece 181 is configured for rotatable, stationaryload and torque bearing, or rotatable load and torque bearingapplications.

The connection system 180 further comprises a flange 194 having a boltpattern 184 and a plurality of bolt holes 186. A shaft 196 extends fromthe flange 194. The flange 194 is configured to be mated to the flange182 on the shaft piece 181, preferably with a gasket 198 having amatching bolt pattern 184. In one exemplary embodiment, the shaft 196 ispart of a fluid delivery system. In another example, the shaft 196 ispart of a rotatable drive or driven system. For example, the shaft 196can be part of a gear box, a motor, a turbine or a compressor. If theshaft 196 is part of a system to be driven, such as a gear box or adriven system for a fan assembly, then the shaft piece 181 is understoodto be connected at its second end (not shown) to a driver equipment,such as a motor. Alternatively, the shaft piece 181 may be connected toan output speed reducing end of a gear box.

FIG. 6 is a schematic cross-section end view of a cooling tower 200provided in accordance with aspect of the present disclosure. Thecooling tower 200 comprises a fan assembly 202 comprising a plurality offan blades 204 driven by an angled fan drive unit or box 206, which isconnected to a drive shaft 208 and which in turn is connected to a fanmotor 210. The fan assembly 202 is connected to an upper deck 212 of thecooling tower 200 and is configured to draw hot air away from thecooling tower out through the shroud 214. In one example, the driveshaft 208 is similarly formed and structured as the shaft piece 181 ofFIG. 5. In other words, the drive shaft 208 comprises a composite tube210 connected at each end to a hub 216, which is connected to a flange.The connection between the tube 210 and the hub 216 at each end may bethe same as described above for the torque tube 116 of FIGS. 1-3. Thus,the drive shaft 208 is understood to include a support tube (not shown),such as an aluminum support tube, pressed fit into each end of thecomposite tube 210. In an alternative embodiment, the drive shaft 208 isconnected directly to the fan shaft and the drive shaft is driven by abelt, which is connected to a drive shaft of a motor.

The present disclosure is therefore understood to include a shaft piecethat is made from a high strength fiber/epoxy composite material havinga length with two open ends, a diameter, and a wall thickness. When usedin combination with a metallic structure, such as when connecting to ahub of the metallic structure, a metallic support tube is first pressedfit into one of the ends of the composite tube with an interference fit.In one example, the total interference is about 0.005 to about 0.012inches with 0.008 being more common. In other examples, the interferenceamount can vary. The metallic support tube is preferably made from analuminum material although stainless steel, carbon steel, and othermetallic materials are also contemplated. The intermediate productconsisting of an outer composite tube and an inner metallic support tubewith an interference fit, which may be referred to as a reinforcedcomposite tube, is then pressed fit into a metallic hub with aninterference fit between the metallic hub and the reinforced compositetube. The total interference with the metallic hub can also be between0.005 to 0.012 inches with other interference range contemplated. Thecomposite tube is thus sandwiched between two metallic interfaces withan interference pre-load on an inside surface of the composite tube andon an outside surface of the composite tube. The sandwiched compositetube may herein be referred to as a reinforced shaft piece.

As disclosed herein, the overlap between the hub and the composite tubeis about 20% to 90% of the outer diameter of the composite tube whilethe overlap between the support tube and the composite tube is about 85%to 125% of the outside diameter of the support tube. The sandwichedcomposite tube or reinforced shaft piece may further include a machinedsurface to control the press-fit arrangement between the hub and thecomposite tube, an undercut in the hub to accommodate adhesive flow, afill hole and a drain hole for applying the adhesive.

The reinforced shaft piece may be used in a number of load and/or torquebearing static or dynamic applications. As disclosed, the reinforcedshaft may be used in automobile applications, in piping applications, incoupling applications, in cooling tower applications, etc. The use canvary by changing the attachment type for the hub. For example, the hubcan be part of a flange with a bolt pattern for bolting to a matingflange, part of a yoke for mating with a universal joint, or part of ahousing that attaches to another housing section. Also contemplated is ahub that has a male or female threaded end to convert the reinforcedshaft piece into a threaded shaft.

Although limited embodiments of composite tube for torque and/or loadtransmissions and their components have been specifically described andillustrated herein, many modifications and variations will be apparentto those skilled in the art. For example, the various hubs connected tothe disclosed composite tube may be connected to any number of flanges,housings, and structures and not necessarily limited to the specificexamples described herein. Also, while exemplary ranges for overlappingand interference fit have been provided, other ranges are contemplateddepending on the scale, size, material, and application, among others.Furthermore, it is understood and contemplated that featuresspecifically discussed for one composite tube for torque and/or loadtransmissions may be adopted for inclusion with another provided thefunctions are compatible. Accordingly, it is to be understood that thecomposite tube for torque and/or load transmissions and their componentsconstructed according to principles of the disclosed device, system, andmethod may be embodied other than as specifically described herein. Thedisclosure is also defined in the following claims.

What is claimed is:
 1. A drive train for a vehicle comprising: an enginecomponent housing comprising a hub having an inside diameter defining abore, an outside diameter, and a thickness therebetween; a compositetube comprising an outer diameter and an inner diameter, said compositetube is pressed fit with the hub of the engine component housing, saidcomposite tube comprising a bore; a support tube mounted inside the boreof the composite tube or over the outer diameter of the composite tubein an interference; and wherein the hub of the engine component housingand the composite torque tube are adhesively bonded together.
 2. Thedrive train according to claim 1, wherein the support tube is made fromaluminum.
 3. The drive train according to claim 1, further comprising ahole formed in the hub of the engine component housing or in the supporttube and wherein an adhesive injection fitting is connected to the hole.4. The drive train according to claim 1, further comprising an undercutformed in the bore of the hub of the engine component housing, to theoutside surface of the hub of the engine component housing, or both foradhesive flow.
 5. The drive train according to claim 1, wherein thecomposite tube has a second end and wherein a second support tube ispressed fit into the second end or over the second end.
 6. The drivetrain according to claim 1, wherein a portion of the composite tube thatis positioned within the bore of the hub of the engine component housinghas a clean-up machined surface.
 7. The drive train according to claim1, wherein the support tube has an end most part and the composite tubehas an end most part and wherein the two end most parts are aligned. 8.The drive train according to claim 1, further comprising a drive shaftlocated inside the composite tube and within the support tube.
 9. Thedrive train according to claim 1, wherein the engine component housingis a bell housing or a slip-on yoke.
 10. The drive train according toclaim 1, wherein the composite tube is made from a combination of fiberand epoxy.
 11. The drive train according to claim 10, wherein thecomposite tube is made from a mix of axial and helical fibers.
 12. Thedrive train according to claim 10, wherein the composite tube has adiameter and wherein the support tube has a length that is approximatelyequal to the diameter of the composite tube.
 13. The drive trainaccording to claim 1, wherein the composite tube is inserted into thehub and an overlap between the hub and the composite tube is about 20%to about 90% of a diameter of the composite tube.
 14. The drive trainaccording to claim 1, wherein an overlap measured in length between thecomposite tube and the support tube is about 85% to about 125% of adiameter of the composite tube.
 15. A method for forming a shaft piececomprising: forming a composite tube comprising a first end and a secondend; said first end comprising a bore, an exterior surface, and aninterior surface; placing a support tube into the bore of the first endin a press-fit arrangement; placing the composite tube with the supporttube into a bore of a metallic structure in a press-fit arrangement withthe metallic structure; and machining an undercut in the bore of themetallic structure prior to placing the composite tube therein.
 16. Themethod of claim 15, further comprising placing a metallic support tubeinto the composite tube at the second end.
 17. The method of claim 15,further comprising aligning an end most part of the support tube with anend most part of the first end.
 18. The method of claim 15, wherein thecomposite tube is inserted into the bore of the metal structure to forman overlap between the metal structure and the composite tube that isabout 20% to about 90% of a diameter of the composite tube.
 19. Themethod of claim 15, wherein the metallic structure is part of anautomobile.
 20. A method for forming a shaft piece comprising: forming acomposite tube comprising a first end and a second end; said first endcomprising a bore, an exterior surface, and an interior surface; placinga support tube into the bore of the first end in a press-fitarrangement; placing the composite tube with the support tube into abore of a metallic structure in a press-fit arrangement with themetallic structure; and pressuring adhesive through a hole formed in thebore of the metallic structure.
 21. The method of claim 20, furthercomprising placing a metallic support tube into the composite tube atthe second end.
 22. The method of claim 20, further comprising aligningan end most part of the support tube with an end most part of the firstend.
 23. The method of claim 20, wherein the metallic structure is partof an automobile.